Reverse stitch attachment for sewing machines



July 24, '1951 R L. ABos ETAL REVERSE STITCH ATTACHMENT FOR SEWINGMACHINES Filed March 26, 1948 Patented .ul'y 24, i951 y2.562mg REVERSESTITCH ATTACHMENT'FO I SEWING MACHINES Ralph L. Abos, Laurence M.Stanfield, and Robert B. Myers, Los Angeles, Calif., assignors to RevcoProducts, Whittier, Calif., a corporation of California ApplicationMarch 26, 1948, Serial No. 17,264

22 Claims.,

This invention relates to sewing machines, and more particularly itrelates to attachments for sewing machine heads of old models foradapting them to perform new functions.

One object of the invention is to provide an easily operable attachmentfor certain models of household sewing machines whereby they may beconverted into what is known as the reverse stitch type, and wherebystitching either backward or forward may be accomplished at the will ofthe operator. f

Another object of the invention is to provide an' attachment of theindicated nature which will serve merely as a replacement of a portionof the stitch controlling mechanism of the original machine.

yStill another object of the invention is to provide a reverse stitchattachment which will be wholly enclosed within the original machinehead except for a manipulating knob projecting from the front of thehead.

It is a still further object to provide a reverse stitch attachmentwhich may be quickly installed to replace the original stitch regulatingmechanism and without the necessity for modifying any of the retainedoriginal equipment. f

In order better to explain the general purposeof our invention, it ispointed out that some of the old model sewing machines, that is, thosewhich are equipped only with the old style conventional backward feedmechanismvby vmeansy of which the material is fed away from the oper--Vator, use a vertical connecting rodr which is known in the trade as afeed fork connection. connecting rod is used to actuate a rocker armwhich causes a serrated feeder mounted in the base of the machine to bemoved back and forth along the stitch line under the fabric beingstitched for intermittently feeding the fabric rearward. A cammechanism, which is used in conjunction with a shuttle actuating device,serves to raise the feeder into operating position during` this rearwardtravel and to lower it out of operating position during its forwardtravel. Another cam at the opposite side of the sewing machine head actsto oscillate the upper end of the connecting rod or feed forkconnection, and during such oscillation such rod is cyclically raisedand lowered through the medium of a guide roller which it carries andwhich travels in an inclined adjustable channel-shaped guide mountedupon an adjacent stationary portion of the machine head. Varying thetilt of the guide upon` the pivot by which it is carried` serves toincrease or reduce the throw of the connecting rod and the stroke of thefeed dog and thereby lengthen or shorten the stitch. In connection withthe present improvement, this guide is mounted so that it may be rockedabout its pivot to tip it to one side or the other side of the pivot, i.e., either 2 l '.j, rearward or forward, whereby thev movement off' thefeed dog may be correspondingly reversed and as a consequence thedirection of the stitching"l will be reversed. When the guide is in aneutral or horizontal position, no stitch isy produced, but

as the guide is tippedl in either direction to al greater or smallerdegree, the stitch in a corre# sponding direction becomes accordinglylonger; or shorter.

However, sincey it'is normally desired to main#` tain a stitch ofconstant length, it is desirablef that any reverse stitch mechanism besuch that, the length of stitch be exactly the same 'when reversed as itwas before reversal. l 7

It is, therefore, also an object of this invention'f to employ reversestitch mechanism which willi act, not only to tip the guide so that thestitch; may be reversed, but will also automatically `pro-1 vide forstitches of exactly equa1 length in the` opposite directions whenreverse stitching is beingf accomplished. ,i

Additionally, it is an object of the invention to, provide a reversestitch mechanism by means of.I which lthe operator may hold the parts inreverse, stitching position as long as required, the parts;automatically returning to conventional stitching; position upon releaseof the mechanism by they operator, that is, so that the fabric is fedback-l: ward. i '1.

It is a furtherobject to providel in a reversev stitch attachment meansfor maintaining the stitch-length adjustment against unintentionalchange during stitch-reversing operations. l

Other objects and features of the invention will appear to those skilledin this art upon refer-' ence to the following specification and theaccom-51 panying drawing wherein certain embodiments are disclosed forthe purpose of illustration.

In the drawing: i

Fig. 1 is a side elevation of a conventional old` style sewing machinehead indicating applicationfof an attachment of the present inventionVthereto for the purposev of adapting the machine to re-L verse stitchoperations; 'l Fig. 2 isy a vertical cross sectiontaken on the;1ine2-2ofFig.1; Fig. Bis an enlarged detail showing the channel guide inend elevation and showing the relation; ship of an offsetting adapterand the guide roller'j carried thereby with respect to the channelguideand the actuating means therefor', *511 Y' Fig. 4 is a longitudinalsection onI n enlarged scale viewed in the directioncf'Figp;. i ff'f fFig. 5 is a side elevation lshowing therecipro cable shaft of Fig. 4rotated about 180; Fig. 6 is a cross section .takenfon the line-f6ofFig.4; Fig. 7 is a fragmentary detail 'of a triangular; groveprovided` in the 4reciprocating,shaftgfor;

In Figs. 1 and 2 there is disclosed a conventional sewing machine head l'which in the table I6.

I1 and pulley I8 driven by a belt -I9 are shown affixed to aconventional drive `shaft 26. ywhichy is provided with variouseccentrics or cam mechanisms, one of which reciprocates a needle bar 2|carrying a needle 22, the bar 2l being "located in the adjacent portionof the head l5 'which supports a conventional 'presser foot 23 above aslot 24 in the Work table I6.

,fIhe shaftZO carries an eccentric 25 which oscillates a fork orAbifurcation I26 of a connecting xfodvZwotherwise known as a feed forkconnection. AThe lower end of the rod 28 is .pivoted and supported at 29upon a short arm 30 on a rock shaft 3| located below` the work table IB.At the left end of the shaft 3l, as'shown in Fig. 1, and at apointa'dj'a'centthe needle bar "2 l, the upper side of the shaft 3l isprovided with'upstanding arms '32 which are pivo't'a'lly connected t'o'ayoke 33, one 'branch of which extends rearward iinderth'e'table 'l''andcarries on the upper side vat'its 'rear "end'a usual feed'dog 34comprising a plurality of/fee'd teeth 'whichnormally project'up'throughjthe's'lot 24 inthe 'work table to feed fabric heldin engagement'therewith by means of the presser `'foot 23 :when the llatter has beenplaced in lowered position by'well known means. 'The other ybranch "ofthe l'yoke 33 carrie's'fa -pin orrolle'r35- Fig.-2) which engages-in acam groove of a cam 36 operated 'from the drive-shaft''ZlJ inconjunction with a shuttle-in a wllknownnianner-'by means not shown. Thecam l36 is transversely reciprocated with-respect toth'e AshowingoflFig. 2 -so thatltlre'feeddog'll is raised in the conventional'mannervthrough the" slot '24# into fabric f engaging :position-'as the feeddog ismovedlrearward by the yyokef.33, the feed dog being drawn downbelow the work `table |6.,by==the eam=36during movement of the-'feed dogforward. I

s :The Iattach-ment' mcorpQra-.tng :the present in.- vention makes it;possible l for the effective movements .of the-feed dogq34 with respect-fto .the movement -of the-cam 3,6 Ito `be reversed at twill, so thatthe feed dogmay be caused to `move forward in reversevstitchrelationship `whenthe cam 36 raises it Vup 4into fabricengaging-position,

the feed dogbeing then drawn down nbelow the table l lli by the cam:.tovdisengage the `fabricl as the Yoke 33 lprepares to 'drive the feeddog '.34 rearward, the length of the stitch to be the sarne nbofthdirections. l'This normal' vertical'move ment'of the connectingro'd'ZB'- to effect the described movements of the "rck Shaft "3|, theykeaa. and' the feed dcgsa is effected through theA medium of a guideroller 48 pivotally mounted on" the' rod 28 and 'operating in'iachannel' 4I' (Fig. 4 ),'in one side of a tiltable channelzguidei42pivotally` mounted on'the head I"5"by a bearingi43 and' by 'being'ied'upon a shaft 44 rotatable 'in the bearing 43. n

Inf conventional'construction' and practice, the

guide roller 40v pivotally mounted on vthe con-v aperture and being alsoon the center line cf--the` Shaft'f44vwhenthe channel guide 42 is in itszero Stitch position.

-'I-Iowever, this conventional mounting provides for tipping cf thechannel guide to one side only, andjhencelperrnits stitching in onedirection only. In connection with the .present invention, an adapter isrequired for the purpose of mounting the roller 40 on an axislsen-iewhat out of alignment with the axis of the Iaperture 28a.

This adapter comprises an offset centering guide pin y46 which directlycarries the roller 4U and is xedly supported by an oisetting plate 48which in :turn is xedly carried on an anchoring shank 50 secured in theaperture 28a of the connecting y.rod 28. A convenient means lformounting the adapter in the aperture 28a is thatindicated by threadingthe outer end of the shank 5U as shown and'femploying a nut 52 forbinding the voffsetting plate 4B .against the .opposite face-.of theconnecting rod 28. .Theplate 4,3 also serves as a. :thrust bearing f-Ort e roller 4,9 which in turn causes` Athe plate 48 to clear ,theed'gevof the-channel guidev42`. l v y f v The extent .of the offsetbetween the @entering pin 46 .and the vanchoring sha-nk .iisfsvfh @5&9align the center 0f the roller with the (center 0f `the channel .guide42, which .is on ,the axis -of the Shaft 4,4 when these Darts' aremiddle or neutral positions. In practice,"

, exact distance andfangleimay -varylighily amount of the offset between,C t rsiissxjnell. beine approximately;Onefesllth A@Tf an 111.19211@1.14, the centering pin 46 is Adisguised ,at an angleci.y about-15upward v@metothe left With lpet. Y the shank 50, as the parts are Viewedin g a. Desired relatnships .between `all ef, the @et tme mechanismsvfor kthe .feeddggian the Smidt regulating mechanism are thus obtained.,-The,

' diierent models.

`Since .the direction of movement :of the feed dog r34 through :thev4.feedingv portion vof path is governedl by fthe 4direction vci? v.inlinaticn of the channel guide v472, and since 4the length-9i Stitch ineither :direction 11S governed .by fthe da, aree Qfinclinauon ofthethannel guid??? inthe respective direction. the latter Servesbeth-.asn feed regulator and as a Stitch reverser.- "lhe p9: Sition ofthe ,channel guide 42 `with respect t0 the adjacent face-0f theconnectinecd :2.8 is um tained by ftheShaI-t 1.4 which inturn is main:-tained' in therheadlies-through the medium'f an integral f head bilVbearing against 'an appro.- nriate :spring Washer .55 whicnlmay'bmeconviene ient1y= disposed fin .a ecou-ntersink 56.. ,Selectiqn of 4.thedirection 'and degree of :inclination of the Q hannel.. guide -'-.42,and Aconsequently iselectionrifi thezidi-rectionzof v stitch andof the:length of :stitch is'easfly accomplishedby:partial rotationlof thechannelfguide 42v and itsshaftM :against Lthexten:` sion lof Sthe'spring.washer 155 through the :me-- diumy v. of :an .rupstanding f nger 158..under control of the stitch.` reverse=mechanjsmof this i-nventionIwhich fis generally indicatedatl. In .order thatithe'ngerl'B Lmayactuatethe channelguide 4 2, .the upper-.end of the finger. isf provided.ewitna .balli-type: headll I which extends intoa .socken-82' int-heunderside-ofthe )lower flange Ma-'of Athe channel guide 42 below `thechannel 14|, as'fbest illustrated in 1'l-igs.-4 and -5. iThe-headflil-is urged' intofsealing position inthe socketl62 through-themedium. of LaA springf63 disposed: about 'the nger 58; the upper end -ofthe spr-i-ng'l53 bearing againstr an annular collar64 onthe pinl68'-be1owthe head 61. eA-t least '-fthe Ylowerflange 42a is-preferably1for-medon the -arc'lof a circle wherebyhtof'avoi'd' any* possible 1interference of Athe annular collar' lidiiwth thelmovementof-*lthe'lowerl'langei42aetoi extremeltilted-positions. The lower end ofthe' .i .l Operation f vWhen the stitch reversing'mechanisin o f thisinvention is assembled as illustrated Figs and placed in operativeposition as indicated'in Fig. 2, the coil spring Vto projects the shaft1li, the vbarrel S and the up'staiidiri'gl 'nger '58 iii-'- ward to thelimit of movement determined by the position of the triangular groove 83so that'1 if `the ball detent 82 is not held in a neutral ipo--'siltiorl by 'the point '84 of the groove B3, the

channel guide V112 is tipped in adirection opposite to that indicated iniig. 4, thev inner 'end oi the skirt 99er the knob-12 rying near theannular flange r88 of the sleeve 15. Under these condi'- tions the.threads e of the sleeve 15 are bound in the corresponding threads of'the casting l5, and the nut 9| and the iian'ge 88 .serve 'as lock nutsfor each other. By pulling the knobl 'I2 outwardand holding it manuallyin such position against the spring 88, the stitching is reversed. Uponrelease of the knob, the spring to returns and holds the .parts innormal or for- Ward stitching relationship. By rotating the knob T2, theshaft 'I8 is rotated to bring the triangular Ygroove 83 into anydesiredposition of adjustment with respect to the ball detent a2 whichis disposed in a .fixed position. As seen in Fig. 4, the ball detent 82is disposed 'at the bottoni of the attachment, this relationship being'also shown in Fig. 6. f the shaft l0 is rotated to the right, as viewedlin Fig. 6, vto the limit 'of its movement, the wide end of thetriangular Agroove '83 is brought into alignment with the ball detent82, the Vdetent 8 2 at this position coming into contact with theadjacent .portion of the elongated pin 95 .positioned in thelongitudinally extending vgroove 84 at the surface of the portion 10a ofthe shaft 'IIL` With this relative relationship between the ball detentB2 'and the groove 83, pulling the knob 'l2 outward to withdraw theshaft T0, and return of the shaft 18 to its retracted position by meansof the coil spring SUwill result in the maximum stroke of the shaft 10andin consequent maximum rock of the channel Vguide v42. Such relativeposition of the groove 8 3 is indicated in Fig. 5.` In this position ofthe groove 83,'the length of stitch Will be the maximum both when theknob "l2 is drawn outward until the ball detent Y82 strikesthe rearwardside sof.

the groove 83 on the path 8B, and when theshaft 10 is allowed to bereturned to Athe opposite -position by the coil spring 80 when the balldetent 82 strikes the opposite side of the/groove '83 o'n the path as.The ydirection of stitch will be changed as rapidly as the knob 12 ismoved be-` By rotating.

tween its two extreme positions. the shaft I0 to the left from theposition of Fig. Stoward the position of Figs. 4 and 6, 'the frictionjoint at the 'cupped spring washer permitting such rotation, anyintermediate position of the ball detent 82 with respect to the groove83 may be had, such 'as that 'illustrated inV Fig'. '7. Under thesecircumstances 'the length of stitch in both directions will be 'cor'-respondingly reduced. By continuing rotation or the shaft 1o to theleft, the rounded point; 84 of the groove 83 will be brought up aboutthe ball deten't 82 at the neutral position of the shaft Y'Ill and itsgroove 83. no stitching whatever.

From the foregoing, it will be apparent that Here, there will be theshaft 10 and its triangular groove 83 Inay` be rotated through the knob12 vto bring 'theL groove 83 into any position of rotational adjust`ment with respect to the ball detent 82 for. ythe purpose ofaccomplishing any stitch length ree quired, 'and -it will also beapparent that the di rection of stitch will be reversed as the shaft 10Ais reciprocatecl through the medium of pull upon the knob lf2 andthrough the medium of the ree turning influence of the coil spring whenthe knob 12 is released by the operator. By making the sides of thetriangular groove 83 symmetrical so that the .paths 85 and 86 forContact of the ball detent are arranged symmetrically with respect tothe corresponding Adiameter vof the lshaft .18., the length of thestitches. in the opposite 4'directions will be exactly the same for a.given setting. It will also be apparent from the foregoing thatconversion from an old style sewing machine head providing for stitchingin one direction only, as previously explained, may be quickly effe;fected merely by removing the old threaded mounting from the threadedaperture 16 ofthe sewing machine head i 5, removing the old ch'an'e. nelguide 42 and the mounting for its roller 48 and substituting the presentchannel guide 4Z and the adapter 45 to position the roller "48, and thenmounting the stitch reversing 'mechanism 6D of this invention in themanner above 'de-'- scribed. f Inasmuch as variations of the genericinvene tion herein disclosed will no doubt become 'ape` parent to thoseskilled in this art, it is intended to cover all such modifications `asfall within the scope of the claims.

We claim as our invention: 1. In combination in a reverse stitch attachement for sewing machines: a shaft adapted to be rotatably and axiallyreciprocably mounted in a sewing machine head with its inner end adaptedto be connected to a stitch control member to shift the latter; stopmeans adapted to be carried by said head; and engaging means `at an-intermediate position on said shaft to limit vmove-l ment. of saidshaft in both of its reciprocating-- movements by engagement with saidstop mozilla'I said 'enga-ging ymeans being adjustable with ire speelsto said stop means for engagement with .said stop lmeans 'at amultiplicity of adjusted' positions in both reciprocating movements to;vary 'the amount of 'shift `of said control meme;

bert

' 2. n combination as in claim i wherein the adjustment of said engagingmeans is accome;

plislied by relative rotation of said shaft, the combination includingmeans for releasably ree taining said Ishaft and its eng-aging means initsv rotatably 'adjusted positions.

l"3. `Acom'lsiination as in claim 2 wherein 'said' engaging meanscomprises two opposed, "sy'm'e: metrically arranged members providingfor eoual stitch lengths in opposite ldirections for each position ofadjustment of said shaft.

said releasable retaining means.

A6. A combination as in claim '5 wherein saidj opposed 'divei'ging wallsare provided by a V- shaped groove in the wall 'of vvsaid shaft, the:axis

ofv said Agroove being directed ciroumferentiall'jf' V around the shaft.

7. A combination as in claim 1 wherein said" engaging means comprisesopposed diverging walls provided by a V-shaped groove formed around thewall of said shaft, said stop means being disposed between said walls ofsaid groove.

8. A combination as in claim 1 wherein said engaging means is in theform of walls of a V- shaped groove cut in the surface of said shaftwith the axis of the V-shaped groove directed circumferentially aroundthe shaft, said stop means being disposed between said walls of saidgroove, and friction means providing for rotatably adjusting said shaftand its groove and for retaining said shaft in adjusted position.

9. A combination as in claim 1 wherein said engaging means comprises twoopposed symmetrically arranged members providing for equal stitchlengths in opposite directions for each position of adjustment. n

10. A combination in a reverse stitch attachment for sewing machines: asleeve having a bore, said sleeve being adapted to be -flxedly mountedin a sewing machine head in line with a stitch control member;reciprocating positioning means slidably mounted in the bore of saidsleeve; detent means carried in said sleeve and projecting into saidbore; diverging wall means provided on the surface of said shaft atopposite sides of said detent means and respectively adapted to engagesaid detent means as said shaft is reciprocated in said sleeve; andmeans for reciprocating and rotatably adjusting said shaft.

11. A combination as in claim 10 including means for maintainingadjustment of said shaft against accidental displacement.

12. In combination in a reverse stitch mechanism adapted for attachmentto sewing machines: a sleeve member provided with a bore adapted toreceive a reciprocating member, said sleeve being adapted to be mountedin a forward portion of the sewing machine head in a relatively fixedposition; a member reciprocally and rotatably mounted in said sleevemember; means for rotatably and reciprocally moving said member mountedin said sleeve member; diverging wall means provided by one of saidmembers in angular relationship with respect to the axis of said sleeve;detent means projecting from an adjacent wall of the other of saidmembers in the position between said wall means for regulating andlimiting the reciprocating movement; and means for preventingdislodgment of the respective members.

13. A combination according to claim 12 wherein said wall means aresymmetrically arranged with respect to each other in opposingrelationship whereby to insure stitch lengths which are equal inopposite directions.

14. A combination according to claim 13 including yielding means forpreventing accidental disturbance of stitch adjustment.

15. A combination according to claim 14 including a spring controlfriction joint for maintaining said adjustment.

16. A combination according to claim 12 including means carried in agroove in one of said members and slidable axially with respect to saidmembers to retain said detent means in operative relationship withrespect to said wall means;

and knob means carried by said reciprocating member to confine saidretaining means in operative relationship.

17. In a combination in a reverse stitch attachment for sewing machines:a shaft adapted to be reciprocally mounted in a sewing machine head withits inner end adapted to be connected to a stitch control member toshift the latter; stop means adapted to be carried by said head;engaging means at an intermediate position on said shaft to limitmovement of said shaft in both of its reciprocating movements byengagement with said stop means; a radially projecting finger mounted onsaid inner end of said shaft; and a ball head on the outer end of saidfinger and adapted to seat in a corresponding socket in said stitchcontrol member to rock the same upon an axis on which it is mounted.

18. A combination as in claim 1 including: a radially projecting fingermounted on said inner end of said shaft; and a ball head on the outerend of said finger and adapted to seat in a corresponding socket in saidstitch control member to rock the same upon an axis on which it ismounted.

19. A combination as in claim 1 wherein said engaging means is in theform of symmetrically arranged walls of a V-shaped groove cut in thesurface of said shaft with the axis of said groove directedcircumferentially around the shaft.

20. A combination as in claim 1 wherein said engaging means comprisestwo opposed symmetrically arranged diverging walls provided on saidshaft transversely to its axis and at opposite sides of said stop means,such walls providing for equal stitch lengths in opposite directions foreach position of adjustment.

21. In combination in a reverse stitch attachment for sewing machines: ashaft to be movably mounted in a sewing machine head with an innerportion adapted for connection to a stitch control member to shift thelatter; stop means adapted to be carried by said head; and engagingmeans provided on said shaft and in the form of side walls of asubstantially symmetrically V-shaped groove cut in the surface of saidshaft, the axis of said groove extending circumferentially around theshaft with said stop means disposed between said walls of said groove,said shaft and groove being adjustable with respect to said stop meansfor engagement of said stop means at a plurality of adjusted positionswith respect to the walls of said groove.

22. A combination as in claim 21 including means providing foradjustment of said shaft and its groove and for retaining said shaft inadjusted position.

RALPH L. ABOS. LAURENCE' M. STANFIELD. ROBERT B. MYERS.

REFERENCES CITED The following references are of record in the iile ofthis patent:

UNITED STATES PATENTS Number Name Date 1,118,271 Diehl et al Nov. 24,1914 1,346,120 Francis July 13, 1920 2,235,552 Gilbertson Mar. 18, 19412,420,480 Ivandick May 13, 1947 2,430,207 Best Nov. 4, 194'?

